JP2020194657A - Luminaire and light guide plate - Google Patents

Abstract

To provide a luminaire which is easy to generate irradiation light that is uniform independent of an irradiation region, and which can easily improve emission efficiency of light, and to provide a light guide plate.SOLUTION: A light guide plate 8 includes: a plate-like part 20 having a plurality of reflection parts 25 capable of reflecting light to the lower side in the height direction on one side in the thickness direction; a curved part 21 curved so as to displace to the upper side in the height direction as it is separated from the plate-like part 20; and an incident part 22 extending to the opposite side from the plate-like part 20 side from the curved part 21, and having a recessed part 34 on an upper side in the height direction. The incident part 22 includes a wall thickness increase part which includes a portion on the plate-like part 20 side in an incident surface 33 constituted by an inner surface of the recessed part 34 and the thickness in the thickness direction gradually increases as it goes to the plate-like part 20 side, on the plate-like part 20 side. A luminaire 1 includes, in addition to the light guide plate 8, one or more LEDs 17 in which at least one part is stored in the recessed part 34, and which emits light toward the incident surface 33 constituted by the inner surface of the recessed part 34.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a lighting device. The present disclosure also relates to a light guide plate of a lighting device.

Conventionally, as a lighting device, there is one described in Patent Document 1. This illuminating device is a disc-shaped ceiling light, and includes an annular substrate, a plurality of light emitting diodes (hereinafter referred to as LEDs), and an integrated light guide plate. The plurality of LEDs are arranged at intervals on a circle centered on the center of the substrate on the mounting surface of the substrate.

Further, the light guide plate has an annular curved portion and a disk portion. The annular curved portion has an annular light entering surface extending in an orthogonal direction substantially orthogonal to the height direction at the upper end in the height direction, and light emitted from a plurality of LEDs is incident on the light entering surface. On the other hand, the disc portion extends in the radial inward direction orthogonally from the annular end portion below the curved portion. The light guide plate has a large number of prisms formed substantially evenly from the curved portion to the disk portion over the entire upper side surface in the height direction. Many prisms reflect the light that guides the inside of the light guide plate in the irradiation direction.

Japanese Unexamined Patent Publication No. 6138644

In the above-mentioned lighting device, since a large number of prisms are formed substantially evenly over the entire upper side surface in the height direction, the brightness of the irradiation light tends to be uniform regardless of the irradiation location. However, the prism has a property of not only reflecting light in the irradiation direction but also leaking light in the direction opposite to the irradiation direction. Then, the leaked light generated by the prism provided in the curved portion is difficult to control and lowers the light emission efficiency.

Therefore, an object of the present disclosure is to provide an irradiation device and a light guide plate that can easily generate uniform irradiation light regardless of the irradiation region and can easily improve the light emission efficiency.

In order to solve the above problems, the lighting device according to the present disclosure has a plate-shaped portion or a plate-shaped portion having a plurality of reflecting portions capable of reflecting light on the first side in the thickness direction at least on one side in the thickness direction. A curved portion that is connected and curved so as to be displaced to the second side in the thickness direction as it is separated from the plate-shaped portion, and a curved portion that extends from the curved portion to the side opposite to the plate-shaped portion side in the thickness direction. A light guide plate having a light receiving portion having a recess on the second side, and one or more light sources that are housed in at least a part of the recess and emit light toward an incoming surface composed of the inner surface of the recess. The plate-shaped portion side includes a portion of the light-entering surface on the plate-shaped portion side, and the thickness in the thickness direction gradually increases toward the plate-shaped portion side. Have in.

Further, the light guide plate according to the present disclosure has a plate-shaped portion having a plurality of reflecting portions capable of reflecting light on the first side in the thickness direction at least on one side in the thickness direction, and a plate-shaped portion connected to the plate-shaped portion. A curved portion that is curved so as to be displaced to the second side in the thickness direction as the distance from the portion is separated, and a curved portion that extends from the curved portion to the side opposite to the plate-shaped portion side to the second side in the thickness direction. It is provided with a light receiving portion having a concave portion, and the light receiving portion includes a portion on the light entering surface formed by the inner surface of the concave portion on the plate-shaped portion side and becomes thicker in the thickness direction toward the plate-shaped portion side. Has a thickened portion on the plate-shaped portion side, which gradually becomes thicker.

According to the present disclosure, it is easy to generate uniform irradiation light regardless of the irradiation region, and it is easy to improve the light emission efficiency.

(A) is a schematic cross-sectional view of the lighting device according to the embodiment of the present disclosure, and (b) is a light guide plate, a plurality of LEDs, and an edge of a housing when the lighting device is viewed from below. It is a schematic plan view which shows the positional relationship of a part. It is a partially enlarged sectional view around the curved portion in FIG. 1A. It is a partially enlarged sectional view corresponding to FIG. 2 in the lighting apparatus of a modification. It is a partially enlarged sectional view corresponding to FIG. 2 in the lighting apparatus of another modification. (A) is a schematic cross-sectional view corresponding to FIG. 1 (a) in another modified example lighting device, and (b) is a schematic plan view corresponding to FIG. 1 (b) in the lighting device.

Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. In addition, when a plurality of embodiments and modifications are included in the following, it is assumed from the beginning that a new embodiment is constructed by appropriately combining the characteristic portions thereof. Also, in the following description, when referring to the front side or the lower side, it indicates the light irradiation side, and when referring to the back side or the upper side, it indicates the side opposite to the light irradiation side. In the following description, the case where the light source is the LED 17 will be described as an example, but the light source may be composed of a light emitting element other than the LED, for example, a semiconductor laser element, an organic EL (Electro Luminescence) element, or the like. It may be composed of a solid-state light emitting element such as an inorganic EL element, and the light source may be composed of an incandescent lamp.

Further, in the following examples, the same components are designated by the same reference numerals in the drawings, and duplicate description will be omitted. Further, the plurality of drawings include schematic views, and the dimensional ratios such as length, width, and height of each member do not always match between different drawings. In addition, when the word "abbreviation" is used in this specification, it is used in the same meaning as the word "roughly speaking", and the requirement of "abbreviation" is satisfied if a person looks like that. .. Further, among the components described below, the components not described in the independent claims indicating the highest level concept are arbitrary components and are not essential components.

FIG. 1 is a schematic view illustrating the structure of the lighting device 1. Specifically, FIG. 1A is a schematic cross-sectional view of the lighting device 1 according to the embodiment of the present disclosure, and FIG. 1B is a light guide plate 8 when the lighting device 1 is viewed from below. It is a schematic plan view which shows the positional relationship of the edge part of a plurality of LEDs 17 and a housing 2. The lighting device 1 is a residential LED ceiling light. As shown in FIG. 1A, the lighting device 1 is mounted including a housing 2 having a substantially circular plan view, an annular LED substrate 4 as a light source substrate, an annular high-reflection sheet 5, and an outer conical surface 7a. A power feeding unit 7, an annular light guide plate 8, and a diffusion cover 9 having a substantially circular plan view are provided. As shown in FIG. 1 (b), the central axes of the housing 2, the LED substrate 4, the highly reflective sheet 5, the mounting power feeding unit 7, the light guide plate 8, and the diffusion cover 9 are located on substantially the same straight line.

With reference to FIG. 1A, the housing 2 is made of metal or resin and has a disc-shaped mounting plate 11. The LED substrate 4 and the mounting power feeding unit 7 are attached to the mounting plate 11 by fastening means, an adhesive, or the like. The mounting power supply unit 7 has, for example, a case 12 and a power supply unit 14 housed in the case 12. In the present embodiment, the case 12 has an outer peripheral conical surface 7a, but may have an annular outer peripheral surface other than the conical outer peripheral surface, and may have, for example, a cylindrical outer peripheral surface. The case 12 is hooked and fixed to, for example, a mounting structure installed on the ceiling, for example, a hook ceiling, a hook rosette, or the like.

The power supply unit 14 is electrically connected to the external wiring by fixing the case 12 to the mounting structure, and AC power is supplied to the power supply unit 14 from the outside. The power supply unit 14 has, for example, a conversion circuit (not shown) provided on a power supply board (not shown), and converts AC power input by this conversion circuit into DC power. The power supply unit 14 supplies the converted DC power to the LED substrate 4. The power supply unit 14 has a switching circuit provided on the power supply board, and supplies or cuts off DC power from the power supply unit 14 to the LED board 4 by a signal or the like from a remote controller (not shown). The conversion circuit and the switching circuit may not be installed in the case 12, and may be installed, for example, on the surface (lower surface) of the mounting plate 11. Further, the switching circuit may be provided on the LED substrate 4. The conversion circuit and the switching circuit may be provided at any place in the lighting device 1.

The LED substrate 4 has an annular substrate 16 and a plurality of LEDs 17 as an example of a light source, and the LEDs 17 are mounted at the same radial position on the mounting surface of the substrate 16 at substantially equal intervals in the circumferential direction. The substrate 16 is composed of, for example, a printed circuit board and may have any hardness, and may be composed of any of a rigid substrate, a flexible substrate, and a rigid flexible substrate. The substrate 16 may have any composition, for example, a paper phenol substrate, a paper epoxy substrate, a glass composite substrate, a glass epoxy substrate, a Teflon (registered trademark) substrate, an alumina (ceramics) substrate, a composite substrate, or the like. Consists of. A lighting circuit is provided on the substrate 16. The lighting circuit electrically connects all the LEDs 17. Each LED 17 is lit by supplying DC power from the conversion circuit to the lighting circuit.

The light guide plate 8 has an integral structure. The light guide plate 8 is made of a transparent material such as acrylic, polycarbonate, or glass, and as shown in FIG. 1A, the light guide plate 8 has a disc-shaped plate-shaped portion 20, a curved portion 21, and a light receiving portion 22. Including. The light guide plate 8 is attached to the housing 2 by, for example, fixing the plate-shaped portion 20 to the lower surface of the highly reflective sheet 5 fixed to the lower surface 12a of the case 12 of the mounting power supply portion 7 with a transparent adhesive or the like. The high-reflection sheet 5 is preferably made of a material having a reflectance of 90% or more, and more preferably made of a material having a reflectance of 95% or more. The highly reflective sheet 5 can be suitably composed of, for example, a metal foil, a polypropylene-based resin composition, or the like. It is preferable that the high-reflection sheet 5 is provided so as to face the entire area of the plate-shaped portion 20 in the thickness direction.

As shown in FIG. 1A, the plate-shaped portion 20 is a plurality of reflecting portions 25 that reflect light on the irradiation side (lower side in the thickness direction) in the thickness direction, which is the first side in the thickness direction. Is held only on the upper side in the thickness direction. Each reflecting portion 25 is composed of a conical recess. The thickness direction of the plate-shaped portion 20 substantially coincides with the height direction of the lighting device 1. In addition, unlike this embodiment, the plate-shaped portion may have a plurality of reflective portions only on the lower side in the thickness direction, or may have a plurality of reflective portions on both the upper side and the lower side in the thickness direction. Further, each reflecting portion may be formed of a truncated cone-shaped or dot-shaped (hemispherical) concave portion instead of a conical shape, and a truncated cone-shaped, truncated cone-shaped, dot-shaped (hemispherical) protruding portion or the like may be formed. It may be composed of.

The curved portion 21 has an annular structure. The curved portion 21 is connected to the plate-shaped portion 20 and is curved so as to be displaced upward in the thickness direction as a second side in the thickness direction as the distance from the plate-shaped portion 20 increases. More specifically, the curved portion 21 extends from the radial outer end of the plate-shaped portion 20 to the radial outer side, and as it goes from the plate-shaped portion 20 to the radial outer side. It curves upward in the height direction. In the present embodiment, in a plan view, the radial direction of the annular light guide plate 8 coincides with the light guide direction of the light on the light guide plate 8.

FIG. 2 is a partially enlarged cross-sectional view of the periphery of the curved portion 21 in FIG. 1 (a). As shown in FIG. 2, the curved portion 21 has a lower curved surface 27 on the lower side in the thickness direction and an upper curved surface 28 on the upper side in the thickness direction. The curved portion 21 is composed of a portion surrounded by a lower curved surface 27 and an upper curved surface 28. Specifically, in the cross-sectional view shown in FIG. 1A, the first annular surface 30 connects the end of the lower curved surface 27 on the plate-shaped portion 20 side and the end of the upper curved surface 28 on the plate-shaped portion 20 side. The second annular surface 31 is composed of a line segment connecting the end of the lower curved surface 27 on the light receiving portion 22 side and the end of the upper curved surface 28 on the light receiving portion 22 side. .. The curved portion 21 is composed of a portion of the light guide plate 8 surrounded by the first annular surface 30 and the second annular surface 31.

With reference to FIG. 1A, the light entering portion 22 extends from the curved portion 21 to the side opposite to the plate-shaped portion 20 side in the light guide direction, and has a thickness of a recess 34 defined by the light entering surface 33. It is held on the upper side in the vertical direction. The recess 34 has an annular structure. As shown in FIG. 2, at least a part of each LED 17 is housed in the recess 34, and specifically, the light emitting surface 17a thereof is housed in the recess 34. Each LED 17 emits light toward an incoming light surface 33 formed of an inner surface of the recess 34. The radial emitted light emitted by each LED 17 travels in the light guide plate 8 after passing through the light entering surface 33 defining the recess 34.

The light receiving portion 22 includes a portion of the light entering surface 33 on the plate-shaped portion 20 side, and the plate-shaped portion includes a wall thickness increasing portion 40 whose thickness in the thickness direction gradually increases toward the plate-shaped portion 20 side. It has on the 20 side. In the present embodiment, the light guide plate 8 has an annular structure, and the thickness of the wall thickness increasing portion 40 becomes thicker toward the inner side in the radial direction (the plate-shaped portion 20 side in the radial direction). There is.

More specifically, in the cross section shown in FIG. 2, that is, the cross section when the light guide plate 8 is cut in a plane including the light guide direction and the thickness direction, the light entry surface 33 is in the thickness direction. A plate-like shape is connected from the first end 38 to the first end 38 on the curved portion 21 side of the first light receiving surface 33a and the first light receiving surface portion 33a formed of a curved curve convex to the first side. It has a second light receiving surface portion 33b extending to the portion 20 side.

The second end 51 on the curved portion 21 side of the first side surface (lower surface) 50 in the thickness direction of the light entering portion 22 is located closer to the plate-shaped portion 20 than the first end 38, and is inside in the radial direction. Located in. Further, the optical axis of the emitted light emitted from the LED 17 is located closer to the plate-shaped portion 20 than the first end 38, and is located inside in the radial direction. The wall thickness increasing portion 40 includes a portion of the light guide plate 8 located between the first end 38 and the second end 51 in the light guide direction.

The second light receiving surface portion 33b is indistinguishably connected to the first end 38 of the first light entering surface portion 33a on the second light receiving surface portion 33b side in the cross section shown in FIG. 2, and is connected to the second side (upper side) in the thickness direction. ) Includes a convex convex portion 55. The convex surface portion 55 may be composed of all portions located on the plate-shaped portion 20 side in the light guide direction from the first end 38 on the light entry surface 33, but the first light entry on the second light entry surface 33b. It may be composed of a part located on the surface portion 33a side.

The second light receiving surface portion 33b may include a diffusing portion 57 that diffuses light in a region opposite to the first light entering surface portion 33a side. The diffusion portion 57 may be formed by forming an uneven structure such as a grain in the region. Alternatively, when the light guide plate is made of a transparent resin, the diffusing portion is a fine particle for scattering light in the region, for example, a pigment such as silica, titanium oxide, or zinc oxide, or a resin, glass, or It may be formed by mixing beads such as zirconia or kneading. Alternatively, the light guide plate may have a main body portion and a diffusion sheet constituting the diffusion portion. Then, the diffusion portion may be formed by fixing the diffusion sheet to the region of the second light entry surface portion of the main body portion on the side opposite to the first light entry surface portion side with an adhesive or double-sided tape. The diffusion sheet may be made of any known material, for example, a sheet-like milky semi-acrylic resin or polyethylene terephthalate (PET) having a light diffusion layer containing light diffusion particles on the surface. May be done.

The diffusion cover 9 has a recess 60 that opens upward in the thickness direction. The diffusion cover 9 may be formed of, for example, a transparent polycarbonate resin to which a diffusing material such as mercury chloride is added, or may have a porous film such as polytetrafluoroethylene (PTFE). The diffusion cover 9 is detachably fitted and fixed to, for example, the peripheral edge of the mounting plate 11 of the housing 2. The diffusion cover 9 diffuses the light arriving from the upper side in the height direction and emits it in the irradiation direction (lower side in the height direction).

In the above configuration, a part R _{1 of} the light emitted from the LED 17 enters the light entering surface 33 of the light entering unit 22, passes through the light entering unit 22, and radiates from the light entering unit 22 in the height direction. It is emitted to the lower side, diffused by the diffusion cover 9, and then emitted to the irradiation region. In particular, in the light guide plate 8 of the present disclosure, the light receiving portion 22 has a wall thickness increasing portion 40 on the plate-shaped portion 20 side in which the thickness in the thickness direction gradually increases toward the plate-shaped portion 20 side. Therefore, a concave lens structure in which the central portion is thinner than the peripheral portion can be locally formed on the plate-shaped portion 20 side of the light input portion 22. Thus, in particular, the lower side of the bending portion 21 can be illuminated with light R ₂ which is diverged by the concave lens structure, it can increase the brightness (luminous intensity) of the light of the bending portion 21 immediately below the region.

Furthermore, another part R ₃ of the light emitted from LED17 is incident on the incident surface 33 of the light input portion 22, for guiding the plate-like portion 20 and travels through the curved section 21. Then, it is reflected downward in the height direction by the reflecting portion 25 of the plate-shaped portion 20, diffused by the diffusion cover 9, and then emitted to the irradiation region. Further, a part of the light that has reached the reflecting portion 25 of the plate-shaped portion 20 leaks upward in the height direction, is reflected downward in the height direction by the high-reflection sheet 5, and then the plate-shaped portion 20 and the diffusion cover. It passes through 9 and is emitted to the irradiation area. In the present embodiment, since the high-reflection sheet 5 is provided at a position facing the plate-shaped portion 20 in the thickness direction, most of the light leaked upward in the height direction by the reflection portion 25 is used as illumination light. And the luminous efficiency can be increased.

As described above, according to the above embodiment, the light receiving portion 22 has a wall thickness increasing portion 40 on the plate-shaped portion 20 side in which the thickness in the thickness direction gradually increases toward the plate-shaped portion 20 side. Therefore, a concave lens structure in which the central portion is thinner than the peripheral portion can be locally formed on the plate-shaped portion 20 side of the light input portion 22. Therefore, the concave lens structure can efficiently diffuse the light incident on the light receiving portion 22, and can efficiently bend the light to the lower region of the curved portion 21, and can realize a wide-angle light distribution. Therefore, the region immediately below the bending portion 21 can illuminate with light R ₂ which is diverged by the concave lens structure, can increase the brightness (luminous intensity) of the light of the region immediately below.

Further, the light that reaches the outer peripheral region and the side surface region of the diffusion cover 9 does not guide the light guide plate 8, but is diffused by the light receiving portion 22 and then directly guided to the region. Therefore, the brightness of the light reaching the outer peripheral region and the side surface region of the diffusion cover 9 can be increased as compared with the case where the outer peripheral region and the side surface region of the diffusion cover are illuminated by the light reflected by the conventional prism. Therefore, since it is possible to brightly illuminate the region directly under the curved portion 21 and the outer peripheral region and the side surface region of the diffusion cover 9, which have conventionally tended to be dark, it is possible to generate more uniform and bright illumination light regardless of the irradiation region. ..

Further, in the case of the present embodiment shown in FIG. 2, since the reflecting portion 25 does not exist in the curved portion 21, the light leaking upward in the height direction does not occur in the reflecting portion of the curved portion 21, which tends to cause loss of light. Therefore, the light emission efficiency can be further improved. Further, there is a problem that it is difficult to form a fine prism structure in the curved portion. On the other hand, in the present embodiment, since the reflecting portion 25 does not exist in the curved portion 21, the light guide plate 8 can be easily formed by injection molding or the like. Therefore, the processing of the light guide plate 8 can be made much easier, the light guide plate 8 can be easily mass-produced, and the manufacturing cost of the light guide plate 8 can be reduced.

Further, the second end 51 on the curved portion 21 side of the lower surface 50 in the thickness direction of the light incoming portion 22 is a plate more than the first end 38 on the second incoming surface portion 33b side of the first light entering surface portion 33a. It is located on the shape portion 20 side, and the optical axis of the emitted light emitted from the LED 17 is located on the plate shape portion 20 side with respect to the first end 38. Therefore, the region of the concave lens structure can be enlarged, and most of the light emitted from the LED 17 can be incident on the concave lens structure. Therefore, it is easier to generate more uniform irradiation light, and the light emission efficiency can be further increased.

Further, in the cross section shown in FIG. 2, the second light input surface portion 33b is indistinguishably connected to the first end 38 of the first light input surface portion 33a on the second light input surface portion 33b side and is convex upward in the thickness direction. It has a convex portion 55 of. Therefore, light can be condensed by the effect of the convex lens of the convex surface portion 55, and more light leaking to the inner space of the illuminating device 1 can be guided toward the plate-shaped portion 20 if the convex lens does not exist. Therefore, since the light leaking to the inner space without the convex lens can be irradiated to the irradiation region through the reflection portion 25 of the plate-shaped portion 20, the light emission efficiency can be further improved.

Further, as for the light emitted by the LED 17, the light in the central region having a small inclination angle with respect to the optical axis tends to be white light as designed, while the light at the end side having a large inclination angle with respect to the optical axis is yellowish light. This yellowish light may cause color unevenness. On the other hand, in the present embodiment, the second light receiving surface portion 33b has a diffusing portion 57 that diffuses light in a region opposite to the first light entering surface portion 33a side. Therefore, it is possible to diffuse only the yellowish light without diffusing the white light, and it is possible to prevent the yellowish light from being locally irradiated. Therefore, the color unevenness of the irradiation light can be reduced and beautiful light can be irradiated. Further, the diffusion portion 57 is located on the light entry surface 33 on the side opposite to the first light entry surface portion 33a side and has a gentle inclination. Therefore, when the light guide plate 8 is formed by injection molding, even when the diffusion portion 57 is formed with an uneven structure such as a grain, the light guide plate 8 can be easily removed from the mold.

The present disclosure is not limited to the above-described embodiment and its modifications, and various improvements and changes can be made within the scope of the claims of the present application and the equivalent scope thereof.

For example, in the above embodiment, the case where the second light input surface portion 33b has a diffusion portion 57 that diffuses light in a region opposite to the first light input surface portion 33a side has been described. However, as shown in FIG. 3, that is, the partially enlarged cross-sectional view corresponding to FIG. 2 in the illumination device 101 of the modified example, the second light receiving surface portion 133b is located in the region opposite to the first light receiving surface portion 133a side. It is not necessary to have a diffuser for diffusing light.

Further, when the second light receiving surface portion 33b is indistinguishably connected to the first end 38 of the first light receiving surface portion 33a on the second light receiving surface portion 33b side and has a convex convex surface portion 55 on the upper side in the thickness direction. Was explained. However, as shown in FIG. 4, that is, the partially enlarged cross-sectional view corresponding to FIG. 2 in the lighting device 201 of another modified example, the second light receiving surface portion 233b is the second light entering surface portion of the first light entering surface portion 233a. The first end 238 on the 233b side may have a conical outer surface 255 that is indistinguishably connected. In short, in the light guide plate of the present disclosure, the thickness of the light entering portion includes the portion of the light entering surface on the plate-shaped portion side, and the thickness in the thickness direction gradually increases toward the plate-shaped portion side. It suffices to have the portion on the plate-shaped portion side.

Further, in the cross section shown in FIG. 1A, the first light entry surface portion 33a in which the light entry surface 33 is formed of a downwardly convex curve in the thickness direction and the curved portion 21 of the first light entry surface portion 33a. The case where the second light receiving surface portion 33b extending from the first end 38 on the side to the plate-shaped portion 20 side is provided has been described. Further, the second end 51 on the curved portion 21 side of the lower surface 50 in the thickness direction of the light incoming portion 22 is a plate more than the first end 38 on the second incoming surface portion 33b side of the first light entering surface portion 33a. The case where the optical axis of the emitted light emitted from the LED 17 is located on the plate-shaped portion 20 side of the first end 38 is described. Further, the case where the curved portion 21 has no reflecting portion at all has been described.

However, the light entering surface does not have to have a light entering surface portion formed of a convex curve downward in the thickness direction in a cross section including the light guide direction and the thickness direction. Further, the second end on the curved portion side of the surface on the first side in the thickness direction of the incoming light portion is located closer to the plate-shaped portion than the first end on the second incoming surface portion side of the first incoming light surface portion. You don't have to. Further, the optical axis of the emitted light emitted from the light source does not have to be located on the plate-shaped portion side with respect to the first end. Further, one or more reflecting portions may be present in the curved portion.

Further, the case where the light guide plate 8 has an annular structure and the light guide direction coincides with the radial direction of the light guide plate 8 has been described. However, as shown below, the light guide plate does not have to be annular. FIG. 5 (a) is a schematic cross-sectional view corresponding to FIG. 1 (a) in the lighting device 301 of another modified example, and FIG. 5 (b) is a schematic corresponding to FIG. 1 (b) in the lighting device 301. It is a plan view.

As shown in FIG. 5, the lighting device 301 may have two identical light guide plates 308, and each light guide plate 308 may have a shape having a substantially rectangular shape in a plan view. Then, the light guide direction may coincide with the width direction or the longitudinal direction of the rectangular light guide plate in a plan view.

Also in the modified example shown in FIG. 5, the light guide plate 308 is a plate having a plurality of reflecting portions 325 capable of reflecting light on the first side in the thickness direction (lower side in the height direction) at least on one side in the thickness direction. It has a shape portion 320. Further, the light guide plate 308 has a curved portion 321 that is connected to the plate-shaped portion 320 and is curved so as to be displaced toward the second side in the thickness direction (lower side in the height direction) as the distance from the plate-shaped portion 320 increases. .. Further, the light guide plate 308 has a light receiving portion 322 extending from the curved portion 321 to the side opposite to the plate-shaped portion 320 side and having a recess 334 on the second side in the thickness direction. The recess 334 extends in the width direction or the longitudinal direction of the light guide plate.

Further, the lighting device 301 includes one or more LEDs 17 whose at least a part is housed in the recess 334 and emits light toward the light entering surface 333 formed by the inner surface of the recess 334. Further, the light entering portion 322 includes a portion of the light entering surface 333 on the plate-shaped portion 320 side, and also has a wall thickness increasing portion 340 in which the thickness in the thickness direction gradually increases toward the plate-shaped portion 320 side. It is provided on the shape portion 320 side. Further, in the plan view shown in FIG. 5B, the light guide directions of the two light guide plates 308 are the same, and the plate-shaped portion 320 of one light guide plate 308 and the plate-shaped portion 320 of the other light guide plate 308 are aligned. , Facing the light guide direction at intervals.

Further, in the cross section when the light guide plate 308 is cut in a plane including the light guide direction and the thickness direction of the light that guides the light guide plate 308, the light entry surface 333 is formed by a curve that is convex toward the first side in the thickness direction. A second light input surface portion 333a that is connected to the first light input surface portion 333a and the first end 338 of the curved portion 321 side of the first light input surface portion 333a indistinguishably and extends from the first end 338 to the plate-shaped portion 320 side. It may have 333b. Further, the second end 351 on the curved portion 321 side of the first side surface (lower surface) 350 in the thickness direction of the light entering portion 322 is located closer to the plate-shaped portion 320 than the first end 338. You may. Further, the optical axis of the emitted light emitted from the LED 17 may be located closer to the plate-shaped portion 320 than the first end 338.

Similar to the light guide plate 8, the light guide plate 308 is also thick so that the second light input surface portion 333b is indistinguishably connected to the first end 338 of the first light input surface portion 333a on the second light input surface portion 333b side. It may have a convex convex portion 355 on the upper side in the direction. Further, the second light receiving surface portion 333b may have a diffusing portion 357 that diffuses light in a region opposite to the first light entering surface portion 333a side. Further, a new modification may be created by applying one or more configurations described in FIGS. 1 to 4 to the light guide plate 308. Also in the illumination device 301 and the light guide plate 308 of this modification, it is possible to generate uniform irradiation light regardless of the irradiation region, and it is possible to improve the light emission efficiency.

1,101,201,301 Lighting device, 2 housings, 8,308 light guide plate, 17 LED, 20,320 plate-shaped part, 21,321 curved part, 22,322 light input part, 25,325 reflecting part, 33 , 333 Light-in surface, 33a, 133a, 233a, 333a First light-in surface, 33b, 133b, 233b, 333b Second light-in surface, 34,334 Recess, 38,238,338 First end, 40,340 Meat Thickness increasing part, 50 First side surface (lower surface) in the thickness direction of the light entering part, 51,351 second end, 55,355 convex surface part, 57,357 diffusion part.

Claims (5)

A plate-shaped portion having a plurality of reflecting portions capable of reflecting light on the first side in the thickness direction at least on one side in the thickness direction, connected to the plate-shaped portion and as the distance from the plate-shaped portion increases, the thickness direction It has a curved portion that is curved so as to be displaced toward the second side of the light, and a concave portion that extends from the curved portion to the side opposite to the plate-shaped portion side and is located on the second side in the thickness direction. A light guide plate with a light inlet and
It is provided with one or more light sources that are housed in at least a part of the recess and emit light toward an incoming surface formed by the inner surface of the recess.
The plate-shaped portion includes a portion of the light-entering surface on the plate-shaped portion side, and the thickness increasing portion in the thickness direction gradually increases toward the plate-shaped portion side. Lighting device on the side of the unit. In a cross section when the light guide plate is cut in a plane including the light guide direction and the thickness direction of the light that guides the light guide plate, the light entry surface is a curved line that is convex toward the first side in the thickness direction. A first light inlet surface portion to be configured, and a second light inlet surface portion that is indistinguishably connected to the first end of the first light inlet surface portion on the curved portion side and extends from the first end to the plate-shaped portion side. Have,
The second end of the light receiving portion on the first side surface in the thickness direction on the curved portion side is located closer to the plate-shaped portion than the first end.
The lighting device according to claim 1, wherein the optical axis of the emitted light emitted from the light source is located closer to the plate-shaped portion than the first end. A claim that the second light input surface portion is non-differentiably connected to the end of the first light input surface portion on the second light input surface portion side and includes a convex surface portion that is convex on the second side in the thickness direction. Item 2. The lighting device according to item 2. The lighting device according to claim 2 or 3, wherein the second light receiving surface portion includes a diffusing portion that diffuses light in a region opposite to the first light receiving surface portion side. A plate-shaped portion having a plurality of reflecting portions capable of reflecting light on the first side in the thickness direction at least on one side in the thickness direction.
A curved portion that is connected to the plate-shaped portion and is curved so as to be displaced to the second side in the thickness direction as the distance from the plate-shaped portion is increased.
A light receiving portion extending from the curved portion to the side opposite to the plate-shaped portion side and having a recess on the second side in the thickness direction is provided.
The meat including the plate-shaped portion side portion of the light receiving surface formed by the inner surface of the recess, and the thickness in the thickness direction gradually increases toward the plate-shaped portion side. A light guide plate having a thickness-increasing portion on the plate-shaped portion side.

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